Despite repeating his account twice, Alkadi's claims were dismissed. A few days later, the bodies of six hostages were discovered in the same tunnel.
The IDF said the two-kilometer tunnel was being used by Hamas as a prolonged hideout.
Israeli forces also found maps of Israeli communities that bordered the Palestinian enclave.
The operation is believed to have significantly disrupted Hamas's terror capabilities in the region.
"Terrorists in the North were on full alert, ready to act" against Israel after October 7, the official senior explained.
The tunnel contained several long-term living areas used by Hamas terrorists throughout the war.
The Jerusalem Post Magazine takes a look back at the year since the October 7 massacre and the Israel-Hamas War.
Yahya Sinwar's plan for October 7 and Hamas's resurrection after the war was planned years in advance.
In 1981, Israel destroyed Iraq’s nuclear reactor, leading Iran, Hamas, and Hezbollah to build underground facilities, countered by bunker-busting bombs like the GBU-28.
IDF Maj.-Gen. Dan Goldfus considers that his breakthrough in overcoming Hamas’s tunnel warfare is not about a single moment in which he had an epiphany but the result of hard, exhaustive work.